1. Field of the Invention
The invention relates to a radio communicating method of performing a data communication among a plurality of nodes in a wireless manner.
2. Description of the Related Art
Recently, a digitization of audio equipment and video equipment such as CD (Compact Disc) player, MD (Mini Disc) recorder/player, digital VTR, digital camera, DVD (Digital Versatile Disc) player, and the like has been progressing. By the spread of a personal computer, a system such that those digital audio equipment or digital video equipment is connected to the personal computer and various controls can be performed by the personal computer has appeared. As mentioned above, as an interface to construct a system such that each digital audio equipment and each digital video equipment are connected or a system such that those equipment and the personal computer are connected, attention is paid to IEEE (Institute of Electrical and Electronics Engineers) 1394.
In IEEE1394, an isochronous transfer mode and an asynchronous transfer mode are supported. The isochronous transfer mode is preferable to transfer a time-sequential data stream such as video data or audio data at a high speed. The asynchronous transfer mode is preferable to, for example, transfer various commands or files. As mentioned above, in IEEE1394, since the isochronous transfer mode and the asynchronous transfer mode are supported, if IEEE1394 is used as an interface, the video data or audio data can be easily transferred between the digital audio equipment and the digital video equipment or those equipment and the personal computer are connected and various controls and an edition can be easily performed by the personal computer.
However, IEEE1394 is a wired interface. To construct the system as mentioned above by the wired interface, a wiring is necessary and a cable is likely to be complicated. In the wired interface, it is difficult to connect a plurality of equipment existing in a remote room in a home.
The applicant of the present invention, therefore, has proposed a wireless LAN which can connect digital audio equipment and digital video equipment or those equipment and a personal computer in a wireless manner and can be used in a manner similar to IEEE1394.
As mentioned above, if the wireless LAN is used, a wiring is unnecessary and data can be easily transmitted among the equipment. However, since there is a limitation in an arrival distance of a radio wave, a data communication cannot be performed among the nodes existing at remote positions. Even if the nodes exist at close positions, a data communication cannot be performed between the nodes between which an object such as a wall or the like which obstructs a radio wave exists. As mentioned above, in the wireless LAN, there is a case where the nodes which cannot mutually perform a data communication exist although they are located on the same transmission path. There is a problem such that a data transmission cannot be performed between such nodes.
It is, therefore, an object of the invention to provide a radio communicating method which can perform a data communication even-to nodes which cannot mutually directly perform a data communication.
According to the invention, there is provided a radio communicating method of mutually performing a radio communication among three or more nodes, comprising the steps of: discriminating whether a communication is possible among the nodes or not; grouping the nodes which can communicate thereamong as a same group; and setting a node which can communicate with two or more groups to a bridge for relaying a data transfer between the two groups.
Whether a communication is possible among the nodes to which data is transmitted in a wireless manner or not is discriminated and the nodes which can communicate thereamong are grouped to the same group. In each node, if a node which can communicate with two or more groups exists, this node is used as a bridge. In case of communicating with the nodes between the different groups, a communication is performed through the node decided as a bridge. As mentioned above, if one node existing among a plurality of groups is used as a bridge, a data communication can be performed even among the nodes of the different groups. Even if the nodes exist at remote positions or an obstacle of a radio wave exists between the nodes, a communication can be performed.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.